Commutativity of rings with constraints involving a subset

summary:Suppose that $R$ is an associative ring with identity $1$, $J(R)$ the Jacobson radical of $R$, and $N(R)$ the set of nilpotent elements of $R$. Let $m \ge 1$ be a fixed positive integer and $R$ an $m$-torsion-free ring with identity $1$. The main result of the present paper asserts that $R$ is commutative if $R$ satisfies both the conditions (i) $[x^m,y^m] = 0$ for all $x,y \in R \setminus J(R)$ and (ii) $[(xy)^m + y^mx^m, x] = 0 = [(yx)^m + x^my^m, x]$, for all $x,y \in R \setminus J(R)$. This result is also valid if (i) and (ii) are replaced by (i)$^{\prime }$ $[x^m,y^m] = 0$ for all $x,y \in R \setminus N(R)$ and (ii)$^{\prime }$ $[(xy)^m + y^m x^m, x] = 0 = [(yx)^m + x^m y^m, x]$ for all $x,y \in R\backslash N(R)$. Other similar commutativity theorems are also discussed

How differential equations influence the tumor growth via mathematical models

This work demonstrates the importance of differential equations to develop mathematical model of tumor growth. Since the malignant tumor (cancer) grows voraciously, the scientists and mathematicians have tried to better understand how it grows. In view of mathematics, the modeling for tumour growth can be divided into two different categories: probabilistic and deterministic. Probabilistic model describes a set of measurement to evaluate the behaviour of individual cells, and deterministic model explains the behaviour of large populations of cells and their growth by changing the state in the transition from an active reproducing cell to a cell that is not reproducing.  In this survey, we first answer the question: How ordinary and partial differential equations (ODE \ PDE) help to provide mathematical models in tumor growth? Secondly, how to use deterministic models and involve the ODE and PDE with some basic aspects of tumor growth to fit any mathematical model. Finally, we provide a relatively comprehensive list of existing models in this area and discuss other representative models in detail together with some possible future developments of mathematical modeling of cancerous cells. Keywords: Cancerous cells, differential equations (ODE/PDE), immunotherapy, mathematical models, tumors

Tea and coffee consumption in relation to vitamin D and calcium levels in Saudi adolescents

Background Coffee and tea consumption was hypothesized to interact with variants of vitamin D-receptor polymorphisms, but limited evidence exists. Here we determine for the first time whether increased coffee and tea consumption affects circulating levels of 25-hydroxyvitamin D in a cohort of Saudi adolescents. Methods A total of 330 randomly selected Saudi adolescents were included. Anthropometrics were recorded and fasting blood samples were analyzed for routine analysis of fasting glucose, lipid levels, calcium, albumin and phosphorous. Frequency of coffee and tea intake was noted. 25-hydroxyvitamin D levels were measured using enzyme-linked immunosorbent assays. Results Improved lipid profiles were observed in both boys and girls, as demonstrated by increased levels of HDL-cholesterol, even after controlling for age and BMI, among those consuming 9–12 cups of coffee/week. Vitamin D levels were significantly highest among those consuming 9–12 cups of tea/week in all subjects (p-value 0.009) independent of age, gender, BMI, physical activity and sun exposure. Conclusion This study suggests a link between tea consumption and vitamin D levels in a cohort of Saudi adolescents, independent of age, BMI, gender, physical activity and sun exposure. These findings should be confirmed prospectively

Investigation and Design of Different Antennas in Solar Cells' Environments with Their Needed Tools

With the spread use of solar cells as a renewable energy source and the wide use of wireless communications, it is interesting to use the solar cell panels as an energy source for rural wireless communications for security and safety. For compactness, it is proposed to embed antennas in the solar cell panels. Therefore, it is proposed to investigate the antenna characteristics within this environment. As such, the characteristics of the solar cells in the radio frequency region should be studied for proper design of the antennas in such an environment. Therefore, a rigorous design approach for antennas in the solar cells' environment is proposed through this work. A practical model of the solar cells in the microwave frequency range is presented using anisotropic surface impedance boundaries. Two different surface impedance measurement setups are exploited to accurately model solar cells. Moreover, measurements of antennas' radiation efficiency are invoked in this work using the Wheeler cap concept in a contactless fashion to perform measurements within solar cells' environments. A novel measurement technique has been proposed extending conventional Wheeler cap capabilities to measure wide band antennas. The technique promotes a straightforward processing procedure and convenient measurement setup. In addition, a simple, fast, and efficient numerical solution for the electromagnetic scattering arbitrary problems is proposed. Based on the uniqueness theorem and the use of novel equivalent problems with Random Auxiliary Sources (\emph{RAS}), more degrees of freedom are added resulting in significantly faster solutions. The proposed technique is expected to provide a significant reduction in the execution time and memory requirements compared to the surface equivalent based Method of Moments (MoM) as the inherent properties of this procedure are used. Various verification and result cases are presented to assess the introduced technique, which is incorporated into different analysis and design problems in this work. Moreover, the RAS method is extended to model antennas in their radiating and scattering modes, which, in turns, is adopted in the reflectarray antenna analysis and design procedures. The introduced solar cells models along with the developed computations and measurement tools are used to develop a design procedure for antennas suited for the solar cells environment. An optically transparent reflectarray antenna integrated with solar cells is proposed as an application of interest that suits satellite communication purposes. Material choice, feed antenna tailored design and rigorous design procedures are presented to enhance the achievable performance of the antenna/solar cells integrated device

Direct Precipitation and Characterization of ZnO Nanoparticles

ZnO nanoparticles are prepared through hydrolysis and condensation of zinc acetate dihydrate by potassium hydroxide in alcoholic medium at low temperatures. Thermal gravimetric analysis (TGA) of the precursor is made in order to specify the temperature range over which the weight loss and thermal effect are significant. X-ray diffraction of the as-prepared specimens shows that the hexagonal (a=3.2459 Å, c=5.1999 Å) structure is the predominant crystallographic structure. According to Scherer’s formula, the average size of the nanoparticles is 22.4 ± 0.6 nm. The structural properties of the synthesized ZnO nanoparticles have been confirmed using the TEM micrographs. The optical energy gap of the ZnO nanoparticles, as obtained from applying Tauc’s equation, is equal to 3.52 eV, which is higher than that of the bulk material. Absorption peak of the as-prepared sample is 298 nm which is highly blue shifted as compared to the bulk (360 nm). Large optical energy gap and highly blue shifted absorption edge confirm that the prepared ZnO nanoparticle exhibits strong quantum confinement effect

In vitro assessment of antimicrobial and anti-inflammatory potential of endophytic fungal metabolites extracts

Endophytes are endosymbiotic microorganisms that act as reservoir of novel bioactive secondary metabolites with antimicrobial, cytotoxic and anti-cancer activities. In the present study, the extracts  of 26 different endophytic fungal strains were screened for their antimicrobial and anti-inflammatory activities. The results showed a wide variety of antimicrobial activities against 12 target microorganisms including three Gram (+) bacteria, three Gram (-) bacteria, 3 yeasts, 2 dermatophytic fungi and one keratinophilic fungus. Four fungal extracts (Aspergillus versicolor, A. awamori, A. niger and Penicillium funiculosum) displayed a broader antibacterial spectrum and inhibited the growth of all Gram (+) and Gram (-) bacterial species. The extracts of 8 endophytic fungi inhibited the growth of the two tested dermatophytic strains (Trichophyton mentagrophytes and T. rubrum). Only eight fungal extracts have an inhibition activity against the keratinophilic fungal strain (Chrysosporium tropicum). The anti-inflammatory assay showed that the extracts of Emericella nidulans, Pleospora tarda and Penicillium funiculosum had good activities in inhibition of protein denaturation reached to 83%, 82.5% and 81.4%, respectively. Also, Emericella nidulans and Pleo-spora tarda recorded the maximum inhibition effect on bovine serum albumin denaturation reached to 95% and 90.7%, respectively. On the other side, Emericella nidulans showed the maximum inhibition activity (69.5%) out of all tested endophytic strains against humun red blood cells membrane stabilization assay. In conclusion some secondary metabolites of endophytic fungi have a promising potential as antimicrobial and anti-inflammatory compounds. DOI: http://dx.doi.org/10.5281/zenodo.83969

Antidiabetic and Antioxidant Effects of Acteoside from Jacaranda mimosifolia Family Biognoniaceae in Streptozotocin–Nicotinamide Induced Diabetes in Rats

BACKGROUND: Acteoside is a phenylethanoid compound isolated from Jacaranda mimosifolia D. Don leaves with a potential antidiabetic effect. OBJECTIVES: This study was designed to investigate the antidiabetic and antioxidant effects of acteoside in streptozotocin-nicotinamide (STZ-NA)-induced Type 2 diabetes in rats. METHODS: Diabetes was induced by intraperitoneal (i.p.) injection of a single dose of STZ (52.5 mg/kg), 15 min following i.p. administration of NA (25 mg/kg). Rats were divided into six groups; Group I: Normal rat group received the vehicle, Group II: Diabetic control group, and Groups III-IV: Diabetic rat groups were treated by either oral acteoside (10, 20, and 40 mg/kg) or pioglitazone (30 mg/kg) for 21 consecutive days. Biochemical parameters were assessed in the serum and liver homogenates. Examination of liver sections for histopathology was also carried out. RESULTS: Acteoside treated rats showed significant lower levels of blood glucose, glycosylated hemoglobin, total cholesterol, triglycerides, and increased serum insulin compared to control diabetic rats. Furthermore, acteoside treated rats, in comparison to the diabetic control, demonstrated significantly reduced malondialdehyde, increased reduced glutathione liver contents, and attenuated pathological alterations in the liver. These effects were comparable to those caused by the standard antidiabetic drug, pioglitazone. In vitro, acteoside scavenged stable free radical 1,1-diphenyl-2-picrylhydrazyl. CONCLUSION: Acteoside could be considered as a potential therapeutic agent for type 2 diabetes mellitus. However, studying further mechanisms underlying its antidiabetic effect is recommended

Structural, Magnetic and Electrical Properties of Co-Doped Barium Monoferrite BaFe2O4

Cobalt-substituted barium monoferrite with theformula BaCoxFe2-xO4 (x = 0.0 – 0.4, step 0.1) has been preparedthrough the sol-gel autocombustion method. Phase purity forprepared samples sintered at 700 and 1050 ̊C was analyzed byX-ray diffraction (XRD) patterns that indicated the formationof the typical orthorhombic phase for the samples. Fouriertransforminfrared (FTIR) spectroscopy was used to investigatethe effect of cobalt doping on the vibrational modes of thestudied samples. Scherrer and Williamson-Hall formulae wereused to define the microstrian and the crystallite size being inthe range of 44.1 to 59.7 nm, which was further confirmed withtransmission electron microscopy (TEM) images. Magneticcharacteristics including magnetic saturation and coercivitywere obtained from hysteresis loops traced using vibratingsample magnetometry (VSM). Magnetic properties werecorrelated with the composition of the prepared samples.Finally, dielectric measurements were operated to furtherconfirm the structural and magnetic analysis

The role of HOXB2 and HOXB3 in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a heterogeneous aggressive disease and the most common form of adult leukemia. Mutations in the type III receptor tyrosine kinase FLT3 are found in more than 30% of patients. Drugs against FLT3 have been developed for the treatment of AML, but they lack specificity, show poor response and lead to the development of a resistant phenotype upon treatment. Therefore, a deeper understanding of FLT3 signaling will facilitate identification of additional pharmacological targets in FLT3-driven AML. In this report, we identify HOXB2 and HOXB3 as novel regulators of oncogenic FLT3-ITD-driven AML. We show that HOXB2 and HOXB3 expression is upregulated in a group of AML patients carrying FLT3-ITD. Overexpression of HOXB2 or HOXB3 in mouse pro-B cells resulted in decreased FLT3-ITD-dependent cell proliferation as well as decreased colony formation and increased apoptosis. Expression of HOXB2 or HOXB3 resulted in a significant decrease in FLT3-ITD-induced AKT, ERK, p38 and STAT5 phosphorylation. Our data suggest that HOXB2 and HOXB3 act as a tumor suppressors in FLT3-ITD driven AML

Genetic relationships and isozyme profile of dermatophytes and Candida strains from Egypt and Libya

Three molecular techniques random amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR) and restriction fragment length polymorphism (RFLP) were employed for identification and to study the genetic relationship among six species of dermatophytes and three species of yeasts isolated from Egyptian and Libyan patients with skin mycosis. Each species was represented by two isolates, one from Egyptian patients and the second from Libyan. RAPD in which four random 10-mer primers and two ISSR primers were used to amplify the DNA fragments of target fungi and RFLP in which two universal primers (ITS1 and ITS4) were used to amplify the internal transcribed spacer (ITS) regions of the ribosomal (rRNA) gene in fungal isolates followed by digestion with HinfI and HaeIII endonucleases was carried out. Three molecular marker techniques showed considerable potential for identifying and discriminating dermatophytes and Candida species and the achieved results confirmed identification based on conventional morphological methods. Results of RAPD and ISSR markers revealed 78.7% genetic similarity (GS) between Microsporum canis and other tested fungi reflecting a relatively longer genetic distance from other isolates of dermatophytes and yeasts. Candida krusei and Candida tropicalis were closely related showing 93.3% GS. C. albicans showed 90.9% similarity with other species of Candida. Epidermophyton floccosum was easily separated from all Trichophyton species showing 87.3% similarity. Unique bands were displayed by certain fungi and can be taken as a positive marker for isolate identification and discrimination. RFLP technique revealed differences in the number (1 to 5) and size (8 to 378 base pairs) of DNA fragments depending on the fungal isolate and restriction enzyme used. Within each fungal species, different isolates of dermatophytes and Candida from Egypt and Libya showed close relationship. Seven isozyme systems namely esterase, peroxidase, malate dehydrogenase, acid phosphatase, glutamate-oxalo-acetate transaminase, Urease and protease were studied to detect the gene expression and genetic variability among the different isolates of dermatophytes and Candida.Keywords: Random amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR), restriction fragment length polymorphism (RFLP), dermatophytes, Candida, isozymesAfrican Journal of Biotechnology Vol. 12(29), pp. 4554-456